One aim is to understand the mechanism of formation of the head of bacteriophage lambda. We have worked out a way to assemble heads in vitro in extracts of induced lambda lysogens. Using in vitro assembly as an assay we will try to purify the protein compounds and to reconstruct the assembly from the pure parts. A second aim is to develop the biochemical genetics of Myxococcus xanthus in order to study multicellular morphogenesis.